US4925733A - Magnetic recording medium - Google Patents

Magnetic recording medium Download PDF

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Publication number
US4925733A
US4925733A US07/173,042 US17304288A US4925733A US 4925733 A US4925733 A US 4925733A US 17304288 A US17304288 A US 17304288A US 4925733 A US4925733 A US 4925733A
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US
United States
Prior art keywords
recording medium
magnetic recording
medium according
film
magnetic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US07/173,042
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English (en)
Inventor
Hiroyuki Imataki
Mizuho Hiraoka
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Canon Inc
Original Assignee
Canon Inc
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Publication date
Application filed by Canon Inc filed Critical Canon Inc
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Publication of US4925733A publication Critical patent/US4925733A/en
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • G11B5/739—Magnetic recording media substrates
    • G11B5/73923—Organic polymer substrates
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/72—Protective coatings, e.g. anti-static or antifriction
    • G11B5/726—Two or more protective coatings
    • G11B5/7262—Inorganic protective coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/90—Magnetic feature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
    • Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
    • Y10T428/264—Up to 3 mils
    • Y10T428/265—1 mil or less
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/3154—Of fluorinated addition polymer from unsaturated monomers
    • Y10T428/31544—Addition polymer is perhalogenated

Definitions

  • the present invention relates to a magnetic recording medium adapted for use in magnetooptical memory, magnetic recording, display device or the like, and more particularly to an improvement in a magnetooptical recording medium allowing regeneration of recorded information by means of magnetooptical effect such as magnetic Kerr effect or Faraday effect.
  • polycrystalline films such as MnBi or MnCuBi
  • amorphous films such as GdCo, GdFe, TbFe, DyFe, GdTbFe, TbDyFe, GdFeCo, TbFeCo or GdtbCo
  • single crystal films such as GdIG.
  • the aforementioned amorphous films are recently considered most preferable for use as the recording layer of magnetooptical recording medium, in consideration of the film forming property at the formation of a film of a large area at a nearly ambient temperature, the recording efficiency for recording signals with a small optothermal energy, and the readout efficiency for regenerating the recorded signal with a high S/N ratio.
  • Particulary GdTbFe is most preferred as the recording layer of the magnetooptical recording medium because of a large Kerr rotation angle and a Curie point in the range of 150° C.
  • amorphous magnetic materials employed in the magnetic recording medium including GdTbFe, are generally associated with a drawback of poor anticorrosive resistance. Lack of reliable stability is the largest problem of these materials as they show deterioration in the magnetic properties when maintained in contact with air and water vapor and are eventually oxidized completely to transparent state.
  • a coating obtained with an appropriate solvent, of an organic resin such as polypropylene, polyethylene, polyamide, polyacrylonitrile, vinylidene chloride, polycarbonate, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, vinylidene chloride-acrylonitrile copolymer etc., or of a plasma-polymerized film of fluorocarbon as disclosed in the Japanese Patent Laid-open No. 90246/1984.
  • an organic resin such as polypropylene, polyethylene, polyamide, polyacrylonitrile, vinylidene chloride, polycarbonate, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, vinylidene chloride-acrylonitrile copolymer etc.
  • inorganic ones consisting of oxides or fluorides are advantageous because of simple film formation by a dry process such as vacuum evaporation or sputtering, but are still deficient in the insulation of air and moisture, thus being unable to achieve satisfactory prevention of deterioration of the recording layer.
  • the coating of organic resins not only requires a complex wet process involving the use of solvents, but also is associated with fluctuating properties of the obtained protective layer.
  • the plasma-polymerized film is ideal for the protective layer because it can be formed in a dry process and is little permeated by air and moisture.
  • formation of such film on the recording layer gives rise to a reaction between the monomer gas and the magnetic layer in the course of plasma polymerization process, often resulting in a deterioration of the magnetic properties.
  • the object of the present invention is to provide a magnetic recording medium with a significantly improved anticorrosive resistance, without sacrificing the magnetic properties of the recording layer.
  • the above-mentioned object can be achieved according to the present invention by forming a plasma-polymerized film on a recording layer with an intermediate layer therebetween.
  • FIGS. 1 and 2 are schematic cross-sectional views showing embodiment of the magnetic recording medium of the present invention.
  • FIG. 3 is a chart showing the result of anticorrosion tests on the examples of the present invention.
  • FIG. 1 is schematic cross-sectional view of an embodiment of the magnetic recording medium of the present invention, in which a substrate 1, composed for example of glass, may be provided with tracking guide grooves for signal recording and regeneration in the form of surface irregularity as illustrated. There is also provided a recording layer 2 composed of an amorphous magnetic film such as GdTbFe, TbFeCo or GdTbFeCo. On said recording layer 2 there are formed an intermediate layer 3 and a plasma-polymerized film 4.
  • Said intermediate layer 3 is composed for example of Al 2 O 3 , BaO, BeO, CeO 2 , In 2 O 3 , SiO 2 , SiO, SnO 2 , Ta 2 O 5 , TiO 2 , ThO 2 , ZrO 2 , MgF 2 , CeF 4 , LaF 3 or a mixture thereof.
  • inorganic material there may also be employed an organic resin layer, but the aforementioned inorganic layer is preferable as it can be formed subsequent to the formation of the recording layer in a same vacuum chamber, without contact of the recording layer with air.
  • the thickness of the intermediate layer 3 though variable depending on the material thereof, is preferably at least equal to 60 ⁇ in order to protect the recording layer from the influence of monomer gas at the plasma polymerization. On the other hand, an excessively thick intermediate layer 3 may develop cracks because of the stress therein. Consequently the thickness of the intermediate layer is preferably in a range from 60 to 10,000 ⁇ , more preferably from 60 to 5,000 ⁇ .
  • the plasma-polymerized film 4 may be composed of any material, but is preferably composed of a strongly hydrophobic fluorinated monomer such as tetrafluoroethylene, hexafluoropropene, hexafluoro-2-butyne, hexafluoro-1,3-butadiene, hexafluorobenzene, octafluoro-2-butene, octafluorocyclobutane, chlorotrifluoroethylene, trifluoroethyne, hexafluoropropylene, vinyl fluoride or vinylidene fluoride, or a hydrocarbon monomer such as ethylene, acetylene, methane, styrene or benzene.
  • a strongly hydrophobic fluorinated monomer such as tetrafluoroethylene, hexafluoropropene, hexafluoro-2-butyne, hex
  • Such monomers form a plasma-polymerized film by means of capacitative or inductive discharge.
  • the plasma-polymerized film is preferably formed with a thickness of 50 ⁇ to several thousand ⁇ , since satisfactory moisture prevention cannot be expected with a thickness less than 50 ⁇ .
  • FIG. 2 shows another embodiment of the magnetic recording medium of the present invention, where in the same components as those in FIG. 1 are represented by same numbers and are omitted from the following description.
  • the substrate 1 is at first provided with a plasma-polymerized film 4', on which formed in succession are a recording layer 2, an intermediate layer 3 and a plasma-polymerized film 4.
  • a plasma-polymerized film 4' on which formed in succession are a recording layer 2, an intermediate layer 3 and a plasma-polymerized film 4.
  • Such structure is effective for preventing the deterioration of the recording layer particularly in case the substrate 1 is composed of a material showing large moisture permeation, such as polymethyl methacrylate (PMMA).
  • PMMA polymethyl methacrylate
  • amorphous magnetic film of GdTbFeCo of a thickness of 1,500 ⁇ as the recording layer in a high-frequency sputtering apparatus.
  • an intermediate layer of SiO with a thickness of 3,000 ⁇ by vacuum evaporation under electron beam heating.
  • the magnetic recording medium thus prepared was subjected to an anticorrosion test in a thermostatic chamber of 85° C. and 85% RH.
  • the obtained result is represented by a curve 11 in FIG. 3, wherein the ordinate indicates the ratio Hc/HcO of the coercive force Hc to the initial value HcO thereof, while the abscissa indicates the period of test in hours. A larger loss in the coercive force indicates a larger degree of corrosion.
  • curves 12 and 13 show the test results on reference examples.
  • a plasma-polymerized film of a thickness of 4,000 ⁇ was formed, without the intermediate layer, directly on the recording layer same as in the Example 1.
  • an SiO film of a thickness of 3,000 ⁇ alone was formed, without the plasma-polymerized film, on the recording layer same as in the Example 1.
  • Tab. 1 summarizes the changes in the coercive force (ratio Hc/HcO) of these magnetic recording media after an anticorrosion test for 1,000 hours at 85° C. and 85% RH.
  • the present invention allows to significantly improve the anticorrosion resistance of a conventional magnetic recording medium without sacrificing the magnetic properties of the recording layer thereof, by forming a plasma-polymerized film on an intermediate layer formed on said recording layer.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Magnetic Record Carriers (AREA)
  • Paints Or Removers (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)
US07/173,042 1984-08-18 1988-03-28 Magnetic recording medium Expired - Lifetime US4925733A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59-172239 1984-08-18
JP59172239A JPS6150236A (ja) 1984-08-18 1984-08-18 磁気記録媒体の製造方法

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US06763713 Continuation 1985-08-08

Publications (1)

Publication Number Publication Date
US4925733A true US4925733A (en) 1990-05-15

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ID=15938194

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/173,042 Expired - Lifetime US4925733A (en) 1984-08-18 1988-03-28 Magnetic recording medium

Country Status (5)

Country Link
US (1) US4925733A (enrdf_load_stackoverflow)
JP (1) JPS6150236A (enrdf_load_stackoverflow)
DE (1) DE3529580A1 (enrdf_load_stackoverflow)
FR (1) FR2571533B1 (enrdf_load_stackoverflow)
GB (1) GB2164269B (enrdf_load_stackoverflow)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0475452A3 (en) * 1990-09-14 1992-12-16 Komag, Inc. Use of a quasi-amorphous or amorphous zirconia dielectric layer for optical or magneto-optic data storage media
US5216665A (en) * 1988-12-28 1993-06-01 Canon Kabushiki Kaisha Information recording medium
US5525392A (en) * 1992-12-10 1996-06-11 International Business Machines Corporation Magnetic recording medium having a fluorinated polymeric protective layer formed by an ion beam
US5677051A (en) * 1993-11-30 1997-10-14 Tdk Corporation Magnetic recording medium having a specified plasma polymerized hydrogen containing carbon film and lubricant
US5682375A (en) * 1994-07-25 1997-10-28 Canon Kabushiki Kaisha Information recording medium and method for recording and reproducing thereof
US5776575A (en) * 1994-04-27 1998-07-07 Canon Kabushiki Kaisha Information recording medium and process for production thereof
US5806388A (en) * 1993-06-04 1998-09-15 Canon Kabushiki Kaisha Process for manufacturing optical recording medium
US6268073B1 (en) 1998-11-09 2001-07-31 Seagate Technology Llc Flash layer overcoat for magnetically-induced super resolution magneto-optical media
US6324131B1 (en) 1999-01-04 2001-11-27 Seagate Technology Llc Low glide magneto-optical recording medium
US6355342B1 (en) 1998-11-18 2002-03-12 Seagate Technology Llc Flash layer overcoat for high density multilayer magneto-optical media
US6381200B1 (en) 1998-11-18 2002-04-30 Seagate Technology Llc Flash layer overcoat for first surface magneto-optical media
US20030228497A1 (en) * 2002-06-05 2003-12-11 Mei-Ling Wu Protective overcoat materials
US6764757B1 (en) 2000-07-10 2004-07-20 Seagate Technology Llc Recording medium with a lubricating layer having increased thermal stability

Families Citing this family (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6240652A (ja) * 1985-08-17 1987-02-21 Tdk Corp 光磁気記録媒体
JPS6243849A (ja) * 1985-08-20 1987-02-25 Tdk Corp 光磁気記録媒体
US4737408A (en) * 1985-08-21 1988-04-12 Tdk Corporation Magneto-optical recording medium having plasma-polymerized protective layers
JPS6246447A (ja) * 1985-08-22 1987-02-28 Tdk Corp 光磁気記録媒体
JP2523279B2 (ja) * 1986-05-02 1996-08-07 ティーディーケイ株式会社 磁気記録媒体およびその製造方法
DE3773531D1 (de) * 1986-05-14 1991-11-14 Teijin Ltd Magneto-optischer aufzeichnungstraeger.
JPS62293536A (ja) * 1986-06-13 1987-12-21 Hitachi Ltd 光磁気デイスク
JPS639050A (ja) * 1986-06-28 1988-01-14 Pioneer Electronic Corp 光磁気記録媒体
DE3635524A1 (de) * 1986-10-18 1988-04-28 Leybold Ag Verfahren zum herstellen von schutzschichten auf magnetischen datentraegern und durch das verfahren hergestellter datentraeger
JPS63113835A (ja) * 1986-10-29 1988-05-18 Kyocera Corp 光磁気記録素子
US4879205A (en) * 1987-01-20 1989-11-07 Kabushiki Kaisha Toshiba Information storage medium and a method of manufacturing the same
JPH01173454A (ja) * 1987-12-28 1989-07-10 Mitsubishi Kasei Corp 光磁気記録媒体
US5571629A (en) * 1987-07-10 1996-11-05 Tdk Corporation Optical recording medium
JP2558011B2 (ja) * 1990-01-31 1996-11-27 インターナシヨナル・ビジネス・マシーンズ・コーポレーシヨン 磁気光学記憶媒体
US5558085A (en) * 1993-01-29 1996-09-24 Aradigm Corporation Intrapulmonary delivery of peptide drugs
US7669747B2 (en) 2007-03-15 2010-03-02 Ethicon Endo-Surgery, Inc. Washer for use with a surgical stapling instrument

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4307156A (en) * 1978-06-13 1981-12-22 Nippon Electric Co., Ltd. Magnetic record member
JPS5819739A (ja) * 1981-07-29 1983-02-04 Sony Corp 薄膜磁気記録媒体
JPS58179939A (ja) * 1982-04-15 1983-10-21 Nec Corp 磁気記憶体
US4414650A (en) * 1980-06-23 1983-11-08 Sharp Kabushiki Kaisha Magneto-optic memory element
JPS59109784A (ja) * 1982-12-15 1984-06-25 Japan Atom Energy Res Inst 高熱流束受熱装置
US4495242A (en) * 1981-04-02 1985-01-22 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4551778A (en) * 1981-02-16 1985-11-05 Fuji Photo Film Co., Ltd. Magnetic recording media and process of producing them
US4565734A (en) * 1983-03-18 1986-01-21 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4583145A (en) * 1983-02-05 1986-04-15 International Business Machines Corporation Apparatus comprising a lubricant-coated magnetic disc and a magnetic head, and method of making said apparatus
US4582746A (en) * 1983-03-01 1986-04-15 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4599266A (en) * 1982-06-18 1986-07-08 Tdk Corporation Magnetic recording medium

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5766549A (en) * 1980-10-09 1982-04-22 Sharp Corp Magnetooptical storage element
JPS57164432A (en) * 1981-04-02 1982-10-09 Fuji Photo Film Co Ltd Magnetic recording medium
JPS5972653A (ja) * 1982-10-20 1984-04-24 Fuji Photo Film Co Ltd 磁気記録媒体
JPS59154643A (ja) * 1983-02-24 1984-09-03 Fuji Photo Film Co Ltd 磁気記録媒体

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4307156A (en) * 1978-06-13 1981-12-22 Nippon Electric Co., Ltd. Magnetic record member
US4414650A (en) * 1980-06-23 1983-11-08 Sharp Kabushiki Kaisha Magneto-optic memory element
US4551778A (en) * 1981-02-16 1985-11-05 Fuji Photo Film Co., Ltd. Magnetic recording media and process of producing them
US4495242A (en) * 1981-04-02 1985-01-22 Fuji Photo Film Co., Ltd. Magnetic recording medium
JPS5819739A (ja) * 1981-07-29 1983-02-04 Sony Corp 薄膜磁気記録媒体
JPS58179939A (ja) * 1982-04-15 1983-10-21 Nec Corp 磁気記憶体
US4599266A (en) * 1982-06-18 1986-07-08 Tdk Corporation Magnetic recording medium
JPS59109784A (ja) * 1982-12-15 1984-06-25 Japan Atom Energy Res Inst 高熱流束受熱装置
US4583145A (en) * 1983-02-05 1986-04-15 International Business Machines Corporation Apparatus comprising a lubricant-coated magnetic disc and a magnetic head, and method of making said apparatus
US4582746A (en) * 1983-03-01 1986-04-15 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4565734A (en) * 1983-03-18 1986-01-21 Fuji Photo Film Co., Ltd. Magnetic recording medium

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5216665A (en) * 1988-12-28 1993-06-01 Canon Kabushiki Kaisha Information recording medium
EP0475452A3 (en) * 1990-09-14 1992-12-16 Komag, Inc. Use of a quasi-amorphous or amorphous zirconia dielectric layer for optical or magneto-optic data storage media
US5525392A (en) * 1992-12-10 1996-06-11 International Business Machines Corporation Magnetic recording medium having a fluorinated polymeric protective layer formed by an ion beam
US5806388A (en) * 1993-06-04 1998-09-15 Canon Kabushiki Kaisha Process for manufacturing optical recording medium
US5677051A (en) * 1993-11-30 1997-10-14 Tdk Corporation Magnetic recording medium having a specified plasma polymerized hydrogen containing carbon film and lubricant
US5776575A (en) * 1994-04-27 1998-07-07 Canon Kabushiki Kaisha Information recording medium and process for production thereof
US5682375A (en) * 1994-07-25 1997-10-28 Canon Kabushiki Kaisha Information recording medium and method for recording and reproducing thereof
US6268073B1 (en) 1998-11-09 2001-07-31 Seagate Technology Llc Flash layer overcoat for magnetically-induced super resolution magneto-optical media
US6355342B1 (en) 1998-11-18 2002-03-12 Seagate Technology Llc Flash layer overcoat for high density multilayer magneto-optical media
US6381200B1 (en) 1998-11-18 2002-04-30 Seagate Technology Llc Flash layer overcoat for first surface magneto-optical media
US6324131B1 (en) 1999-01-04 2001-11-27 Seagate Technology Llc Low glide magneto-optical recording medium
US6764757B1 (en) 2000-07-10 2004-07-20 Seagate Technology Llc Recording medium with a lubricating layer having increased thermal stability
US20030228497A1 (en) * 2002-06-05 2003-12-11 Mei-Ling Wu Protective overcoat materials

Also Published As

Publication number Publication date
JPS6150236A (ja) 1986-03-12
FR2571533A1 (fr) 1986-04-11
DE3529580C2 (enrdf_load_stackoverflow) 1989-12-21
GB2164269B (en) 1987-11-18
FR2571533B1 (fr) 1995-02-10
DE3529580A1 (de) 1986-02-27
GB8520483D0 (en) 1985-09-18
JPH0555942B2 (enrdf_load_stackoverflow) 1993-08-18
GB2164269A (en) 1986-03-19

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